1. Field of the Invention
This invention relates generally to a tire molding mold and more particularly to a tire molding mold comprising a profile ring having an inner circumferential surface corresponding to the outer profile of a tire being molded, including at least the tread surface thereof, and a net ring in contact with and joined to the inner circumferential surface of the profile ring and consisting of a network of ribs and lugs for forming the grooves of the tire being molded; the net ring being disposed on the profile ring.
2. Description of the Prior Art
In general, a tire molding mold has on the inner surface thereof a profile corresponding to the outer circumferential surface of a tire being molded, that is, a tread portion 1 corresponding to the tread surface of the tire and projections 2 corresponding to the grooves of the tire, as shown in FIG. 1. As is well known, the steering stability, travelling performance, road holding performance and noise reduction performance of a tire depend largely on the profile formed by the tread portion 1 and the projections 2 and the dimensional accuracy thereof.
A tire molding mold has heretofore been manufactured by integrally forming the tread portion 1 and the projections 2, or by welding the projections 2 on the inner circumferential surface comprising the tread portion 1, using the plaster mold process, sand mold process, ceramic molding process, metal mold process and other precision molding processes, engraving process, electro-discharge forming process and other manufacturing methods. With these conventional manufacturing methods, therefore, an entire metal mold has to be replaced with a new one every time the profile of a tire is remodelled to improve the performances of the tire, and it is extremely difficult to manufacture tire molding molds having accurate concentricity and roundness. Furthermore, the conventional manufacturing methods involve enormous manhours in final adjustment and finishing, for example, in the final stages of manufacture. As a result, tire molding molds manufactured with these conventional methods involve high manufacturing costs and a long manufacturing time.